Protective ducting

ABSTRACT

There is described ducting comprising a plurality of interconnectible elongate ducting components ( 2, 4 ) which when assembled define an elongate, longitudinally extending internal channel ( 22 ) for receiving a pipe, cable or like elongate member, each ducting component having a shaped inner face ( 14 ) with a longitudinal recess ( 20 ) such that the components can be assembled with confronting inner faces ( 16, 18 ), their respective longitudinal recesses being thereby aligned to form the channel, the ducting further comprising tension bands ( 6 ) for securing assembled pairs of components to one another, wherein each ducting component is provided with a transversely extending internal cavity for receiving a tension band, the cavity having two open ends so that the band can pass through the internal cavity of one ducting component and though a corresponding internal cavity of an adjacent ducting component in order to secure one to the other, at least part of the band being thereby contained and protected within the cavities.

The present invention relates to protective ducting, and in particular,but not exclusively, to protective ducting for pipes, cables and likeelongate members.

Once pipes or cables have been laid, it is desirable to protect themfrom physical damage. The marine environment is particularly demandingin this regard. In the oil industry, for example, pipes such as therisers used e.g. to draw hydrocarbons to the surface and to inject fluidinto a well, can be subject to motion relative to the sea bed andrequire protection from resulting abrasion. Sea bed materials such ascoral may otherwise destroy even armoured risers.

It is known to provide such pipes or cables with a tough, segmentedexterior cladding. An example of such cladding is disclosed in theapplicant's patent GB2260590 and comprises moulded plastics claddingcomponents of generally semi-tubular shape which are assembled aroundthe pipe or cable, each component having a shaped inner face which abutsthe corresponding face of a diametrally opposed further component, thetwo shaped inner faces together defining a channel along the length ofthe ducting which receives the pipe or cable. Male and female matingfeatures, such as nipples and corresponding blind holes, formed inconfronting portions of the inner faces assist in correct alignment ofthe components relative to each other. To secure the ducting together aband is placed around an assembled pair of ducting components, tensionedand then secured. It is known to form a shallow circumferentiallyextending recess in the exterior of the ducting components to receivethe band.

The tension bands are typically of metal and are tensioned and securedin a manner well known in itself utilising a crimped buckle arrangement.It is known to form a shallow recess or “pocket”, in a region of theexterior of the cladding component remote from the join line where thecomponent meets its diametrically opposed counterpart, in which thebuckle sits. This facilitates the tensioning and crimping and providessome protection against damage to the buckle.

While cladding of this type has been highly successful, both technicallyand commercially, it is desirable (with a view to extending working lifeand minimising the likelihood of failure of the cladding) to maximiseresistance of the cladding to physical damage in use.

In accordance with a first aspect of the present invention there isducting comprising a plurality of interconnectible elongate ductingcomponents which when assembled define an elongate, longitudinallyextending internal channel for receiving a pipe, cable or like elongatemember, each ducting component having a shaped inner face with alongitudinal recess such that the components can be assembled withconfronting inner faces, their respective longitudinal recesses beingthereby aligned to form the channel, the ducting further comprisingtension bands for securing assembled pairs of components to one another,wherein each ducting component is provided with a transversely extendinginternal cavity for receiving a tension band, the cavity having two openends so that the band can pass through the internal cavity of oneducting component and through a corresponding internal cavity of anadjacent ducting component in order to secure one to the other, at leastpart of the band being thereby contained and protected within thecavities.

In accordance with a second aspect of the present invention there is anelongate ducting component having a shaped inner face in which is formeda longitudinal recess, the inner face providing confronting surfaces oneither side of the recess for confronting corresponding surfaces of afurther ducting component thereby to form, with the further ductingcomponent, an elongate, longitudinally extending internal channel forreceipt of a pipe, cable or like elongate member, the ducting componenthaving an end region which is shaped to overlap and engage with afurther, longitudinally juxtaposed, ducting component, enablingformation of an elongate duct and having at least one transverselyextending internal cavity for receiving a tension band, the cavityhaving two open ends so that the band can pass through the internalcavity of the component to secure it to a neighbouring component.

The invention permits even the tension bands to be largely or whollyprotected by the ducting components. Problems of abrasion or snagging ofthe bands are thereby overcome.

Specific embodiments of the present invention will now be described, byway of example only, with reference to the accompanying drawings inwhich:

FIG. 1 illustrates in perspective a short length of ducting embodyingthe present invention in an assembled configuration;

FIG. 2 illustrates in perspective the same short length of ducting whenpartly disassembled;

FIG. 3 is a side view of a cap used in certain embodiments of thepresent invention;

FIG. 4 is a perspective illustration of a ducting component embodyingthe present invention; and

FIG. 5 is a view along a radial direction of assembled ducting embodyingthe present invention.

FIGS. 1 and 2 show short lengths of a pair of ducting components 2, 4,joined by means of a tension band 6. It must be understood that, for thesake of representational simplicity, only part of both ductingcomponents 2, 4 is shown, the components being broken off at 8 and 10.It can nonetheless be seen that the ducting components of thisparticular embodiment are semi-tubular, forming a circular duct whenassembled. Circular ducting is convenient to manufacture andadvantageous in many applications. Nonetheless the present invention maybe applied to non-circular ducting. For example, non-circular ductingmay be used to contain bundled members such as cabling or tubing

Each ducting component in the illustrated embodiment has a semi-circularsurface 12 referred to as the “outer” surface since it forms theexterior of the assembled duct and an inner surface 14 which isconcealed within the duct following assembly. The inner surface 14 isshaped to provide flat “confronting” portions 16, 18 and portions 20 ofsemi-circular cross section forming in the inner faces longitudinallyextending recesses which align in the assembled ducting to form alongitudinal channel 22. In use the ducting components are assembledaround a pipe, cable or like member which is received in the channel 22.

The ducting components 2, 4 are aligned relative to each other by virtueof registration features formed at the confronting portions 16, 18 ofthe respective inner faces 14. These are in the present embodiment ofmale and female type, more specifically comprising pips 24 received incomplementary blind holes 26.

The tension band 6 serves to secure one ducting component 2 to the other4. In marine ducting the band is chosen to be metal for its high tensilestrength and the most preferred alloy is known by the referenceUNSNO6625. Titanium may alternatively be used. In accordance with thepresent invention, the tension band 6 is disposed in cavities formedwithin the ducting components 2, 4. Hence in the assembled configurationof FIG. 1 the band is largely contained, and so protected, within theducting components and is seen mainly in phantom. The cavities whichreceive the band extend transversely to the ducting. More specifically,since the illustrated embodiment comprises semi-annular cavities, theycan be said to be diametrally extending. Each cavity is open at both ofits ends and includes a surrounding cavity wall extending between thetwo open ends to freely allow the band 6 to pass therethrough. In eachcase one end opens through a confronting portion 16 of the inner face14, so that in this area the band is not exposed to the exterior. Theopposite end however opens towards the exterior of the ducting so thatthe band's two ends 30, 32 are accessible, following assembly of the twohalves of the ducting, to allow the band to be tensioned and secured. Inthe illustrated embodiment known banding technology is utilised, one endof the band being bent backwards on itself as seen at 34 to retain abuckle 36 formed as a generally flat loop of metal sheet. To secure theband its free end 30 is passed through the buckle 36 and a known bandingtool is then applied to draw the band to a selected tension, crimp edgeregions of the band and buckle, preventing withdrawal of the band, andto snip off spare length of the band's free end protruding beyond thebuckle.

Assembly of the ducting is a time sensitive process and to facilitateinsertion of the tension band 28 to the cavities in the ductingcomponents its free end 30 may be pre-formed to assume an appropriatecurve as seen at 40. Furthermore the openings through which the band isinserted may have widened mouths, more easily to receive the band.

It can be seen in FIGS. 1 and 2 that the buckle 36 of the tension bandsits in a shallow pocket 42 at the ducting's exterior. This pocketserves both to facilitate insertion of the band and to afford the bucklesome degree of protection—being set down into the ducting, the buckle isless prone to being caught in surrounding objects (e.g. rocks on the seabed) or to being abraded thereby than if it stood proud of the ductingsurface. The illustrated embodiment is believed to be innovative in thatthe pocket 42 extends across a join line 44 of the ducting, being formedby aligned part-pockets 46, 48 in the respective ducting components 2,4. Hence the buckle can be placed across the join line.

In an alternative construction (not illustrated) the full pocket isformed on one side of the join line between diametrally adjacent ductingcomponents, the band exiting an opening facing into the pocket on theadjacent component.

In certain embodiments a cap 50 of the type illustrated in FIG. 3 may beprovided to cover the buckle and provide it with further protection. Thecap 50 has a body 52 with an outer surface 54 curved to match and to lieflush with or below the outer surface of the ducting, and a pair offlexible wings 56 which, when the cap is forced into position over thebuckle, are inserted into the annular cavities alongside the tensionband 6, thereby retaining the cap in position. An alternativeconstruction (not illustrated) users a pocket with undercut perimetralwalls and a cap which is a snap fit therein.

FIG. 4 shows a complete ducting component 100. It can be seen that theducting component has a plurality of band-receiving cavities 102, 104,106, 108 at regular intervals along its length. Also end regions of theducting component are shaped to overlap and engage with end regions oflongitudinally juxtaposed components. In the illustrated embodiment,this is achieved by providing a reduced diameter spigot 110 at one endof the component and a socket 112, having an increased internaldiameter, at the other end of the component. The spigot is sized forreceipt of the socket and in the assembled ducting projection of thespigot into the socket provides protection against damage due to ingressof foreign bodies. A tension band lies around the spigot/socketarrangement, in the cavity 108.

To prevent the ducting from being pulled apart longitudinally, jointsbetween longitudinally neighbouring components may be staggered as seenin FIG. 5. Here the longitudinal join line is seen at 150 and the joints152 between longitudinally neighbouring components on one side of line150 are deliberately mis-aligned from joints 154 on the opposite side ofthe line. This staggering of ducting components is itself known.

It can be seen in FIG. 4 that part-pockets 156 are in this exemplaryembodiment arranged along only one side of the ducting component. In theassembled ducting, to bring the part-pockets of the ducting componentsinto register with each other, one component must be rotated 180° abouta lateral axis (i.e. rotated end-for-end) and then longitudinallydisplaced, relative to its diametrally juxtaposed neighbour, to providethe requisite staggering. Alignment features comprising pips 158 andblind holes 160, are positioned (as shown) to allow the components to beassembled when so arranged.

The ducting components in the illustrated embodiments each comprise aunitary plastics moulding. The preferred material is polyurethane, whoseabrasion resistance and resilience are well suited. In order to mouldthe annular recesses in the ducting components a semi-circular member isinserted in the mould, being mounted through its free ends. Followingthe moulding process the member can then be withdrawn from the mouldingalong a circular path.

1. Ducting comprising a plurality of interconnectible elongate ductingcomponents which when assembled define an elongate, longitudinallyextending internal channel for receiving a pipe, cable or like elongatemember, each ducting component having a shaped inner face with alongitudinal recess such that the components can be assembled withconfronting inner faces, their respective longitudinal recesses beingthereby aligned to form the channel, the ducting further comprisingtension bands for securing assembled pairs of components to one another,wherein each ducting component is provided with a transversely extendinginternal cavity for receiving a tension band, the cavity having two openends and a surrounding cavity wall extending between the two open endsso that the band can freely pass through the internal cavity of oneducting component and through a corresponding internal cavity of anadjacent ducting component in order to secure one to the other, at leastpart of the band being thereby contained and protected within thecavities, wherein end regions of the elongate ducting components areshaped to overlap and engage with end regions of longitudinallyjuxtaposed elongate ducting components.
 2. Ducting as claimed in claim 1comprising ducting components, in which an open end of the internalcavity is adjacent a pocket formed in the duct's outer surface such thata band securing arrangement used to secure the band to itself undertension can be located in the pocket.
 3. Ducting as claimed in claim 2wherein each ducting component has in its outer surface part of a pocketformed adjacent an open end of the internal cavity, so that when thecomponents are assembled the part-pockets of adjacent components arealigned forming a pocket which lies across a join line between the twocomponents.
 4. Ducting as claimed in claim 1 wherein the all of theducting components are of a common shape.
 5. Ducting comprising aplurality of interconnectible elongate ducting components which whenassembled define an elongate, longitudinally extending internal channelfor receiving a pipe, cable or like elongate member, each ductingcomponent having a shaped inner face with a longitudinal recess suchthat the components can be assembled with confronting inner faces, theirrespective longitudinal recesses being thereby aligned to form thechannel, the ducting further comprising tension bands for securingassembled pairs of components to one another, wherein each ductingcomponent is provided with a transversely extending internal cavity forreceiving a tension band, the cavity having two open ends so that theband can freely pass through the internal cavity of one ductingcomponent and through a corresponding internal cavity of an adjacentducting component in order to secure one to the other, at least part ofthe band being thereby contained and protected within the cavities,wherein each ducting component has in its outer surface part of a pocketformed adjacent an open end of the internal cavity, so that when thecomponents are assembled the part-pockets of adjacent components arealigned forming a pocket which lies across a join line between the twocomponents, wherein the part-pockets are arranged to register one withanother when adjacent components are rotated one relative to the otherthrough 180 about a transverse axis and longitudinally displaced onerelative to the other.
 6. Ducting as claimed in claim 5 whereinregistration features are provided on confronting portions of the innerfaces to locate the components one relative to the other with theirpart-pockets in register.
 7. Ducting as claimed in claim 1 wherein theinternal cavities are substantially semi-annular.
 8. Ducting as claimedin claim 1 wherein the internal cavities have one end which opensthrough a confronting portion of the shaped inner face, which portionconfronts a corresponding portion of a neighboring ducting component inthe assembled ducting, such that the tension band can pass from one of apair of ducting components into the other of the pair without beingexposed at the exterior of the ducting.
 9. Ducting as claimed in claim 1wherein at least one open end of each of the internal cavities has anenlarged mouth for receiving a free end of the tension band.
 10. Ductingas claimed in claim 1 wherein at least an enc region of the tension bandhas a pre-formed curve to facilitate insertion into the an internalcavity.
 11. An elongate ducting component having a shaped inner face inwhich is formed a longitudinal recess, the inner face providingconfronting surfaces on either side of the recess for confrontingcorresponding surfaces of a further ducting component thereby to form,with the further ducting component, an elongate, longitudinallyextending internal channel for the receipt of a pipe, cable or likeelongate member, the ducting component having an end region which isshaped to overlap and engage with a further, longitudinally juxtaposed,ducting component, enabling formation of an elongate duct and having atleast one transversely extending internal cavity for receiving a tensionband, the cavity having two open ends and a surrounding cavity wallextending between the two open ends so that the band can freely passthrough the internal cavity of the component to secure it to aneighboring component.
 12. An elongate ducting component as claimed inclaim 11, wherein an open end of the internal cavity is adjacent apocket or part pocket formed in the duct's outer surface such that aband securing arrangement used to secure the band to itself undertension can be located in the pocket.
 13. An elongate component asclaimed in claim 12 wherein each ducting component has in its outersurface part of a pocket formed adjacent an open end of the internalcavity, so that when the components are assembled the part-pockets ofadjacent components are aligned forming a pocket which lies across ajoin line between the two components.
 14. An elongate component asclaimed in claim 13 shaped to allow ducting to be constructed from a setof identical such components.
 15. An elongate component as claimed inclaim 14 wherein the part-pockets are arranged to register one withanother when adjacent components are rotated one relative to the otherthrough 180 about a transverse axis and longitudinally displaced onerelative to the other.
 16. An elongate ducting component having a shapedinner face in which is formed a longitudinal recess, the inner faceproviding confronting surfaces on either side of the recess forconfronting corresponding surfaces of a further ducting componentthereby to form, with the further ducting component, an elongate,longitudinally extending internal channel for the receipt of a pipe,cable or like elongate member, the ducting component having an endregion which is shaped to overlap and engage with a further,longitudinally juxtaposed, ducting component, enabling formation of anelongate duct and having at least one transversely extending internalcavity for receiving a tension band, the cavity having two open ends sothat the band can freely pass through the internal cavity of thecomponent to secure it to a neighboring component, wherein the cavity issubstantially semi-annular.
 17. An elongate component as claimed inclaim 11 wherein the internal cavities have one end which opens througha confronting portion of the shaped inner face, which portion confrontsa corresponding portion of a neighboring ducting component in theassembled ducting, such that the tension band can pass from one of apair of ducting components into the other of the pair without beingexposed at the exterior of the ducting.
 18. An elongate component asclaimed in claim 11 wherein at least one open end of each of theinternal cavities has an enlarged mouth for receiving a free end of thetension band.
 19. Ducting according to claim 1, wherein the elongateducting component has a spigot on one end region and a socket on theother end region, the spigot of one elongate ducting component adaptedto engage the socket on an end region of a longitudinally juxtaposedelongate ducting component.
 20. Ducting according to claim 11, whereinthe elongate ducting component has either a spigot or a socket on theend region, the spigot or socket of one elongate ducting componentadapted to engage the socket or spigot on an end region of alongitudinally juxtaposed elongate ducting component.
 21. Ductingaccording to claim 1, wherein at least one tension band extends aroundone of the end regions to secure longitudinally juxtaposed elongateducting components together.
 22. Ducting according to claim 11, whereinat least one tension band extends around the end region to securelongitudinally juxtaposed elongate ducting components together.